Phasor Diagram
A graphical representation of AC voltage and current relationships in a transformer showing magnitude and phase angle.
A phasor diagram graphically represents the relationships between voltages, currents, and flux in a transformer using rotating vectors. Essential for understanding vector group designations, voltage regulation, and power factor.
For a transformer, the phasor diagram shows: applied voltage V1, induced EMF E1, impedance drops (I1R1, I1X1), flux, secondary E2, V2, and load current at the appropriate power factor angle.
Used to determine: voltage regulation, efficiency at various loads, voltage ratio under load, parallel vector group compatibility.
QDTB provides phasor analysis during transformer specification. See selection guide for application guidance.
Related Products
Related Terms
Vector Group
Standardized designation of transformer winding connections and phase displacement between HV and LV.
Voltage Regulation
The change in secondary voltage from no-load to full-load as a percentage, indicating voltage stability.
Power Factor
The ratio of real power (kW) to apparent power (kVA) indicating how effectively electrical power is utilized.
Impedance (%Z)
Total opposition to current flow in a transformer as a percentage, determining fault current and voltage regulation.
More Terms Starting with “P”
Power Transformer
A large transformer (>10 MVA) used in transmission networks for stepping voltage between system levels.
Power Factor
The ratio of real power (kW) to apparent power (kVA) indicating how effectively electrical power is utilized.
Partial Discharge (PD)
Localized electrical discharges in small insulation regions not bridging electrodes, indicating defects or aging.
Prefabricated Substation
A factory-assembled complete substation integrating transformer, switchgear, and protection for rapid installation.
More in “Electrical Fundamentals”
Apparent Power (kVA)
The total power in an AC circuit combining real (active) and reactive power, measured in kilovolt-amperes (kVA).
Eddy Current
Circulating currents induced in conductive materials by changing magnetic fields, causing energy losses in transformers.
EMF (Electromotive Force)
The voltage generated by electromagnetic induction in a transformer winding, proportional to flux change and turns.
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